THE PRESENT INVENTION relates to an air-bag arrangement, and more particularly relates to an air-bag arrangement intended for use in a motor vehicle such as a motor car.
It has been proposed to provide an air-bag arrangement which incorporates an inflatable element which is associated with a gas generator adapted to inflate the inflatable element in the event that an accident should occur. The inflatable element, when inflated, forms a substantially flat structure which is located between the occupant of the vehicle and adjacent the side of the vehicle, thus covering the door or windows provided at the side of the vehicle. The flat structure may be termed a xe2x80x9cside curtainxe2x80x9d. The inflatable element may initially be located, in the uninflated state, in a housing or recess formed in the roof of the vehicle extending, across the top of the door opening.
An inflatable element of this type may be of substantial benefit in a side impact situation, or in a roll-over situation, and consequently the gas generator may be adapted to inflate the inflatable element in response to a sensor adapted to sense such a side impact, or roll-over situation.
The inflatable element, when inflated, provides protection for the head and shoulder of the driver against all impact with the structure forming the side of the vehicle. Thus, the inflatable element may prevent the head of the occupant striking part of the vehicle which might injure the occupant, such as the xe2x80x9cBxe2x80x9d-Post, if the occupant is a front seat occupant, or striking the xe2x80x9cCxe2x80x9d-Post if the occupant is a rear seat occupant. The inflatable element also serves to prevent the occupant of the vehicle being partially or completely thrown out of the vehicle through the window opening.
The present invention seeks to provide an improved air-bag arrangement of the type generally discussed above.
According to this invention there is provided an air-bag arrangement in a motor vehicle, the air-bag arrangement comprising an inflatable element formed of fabric and gas generator means adapted to inflate the inflatable element in response to the sensing of predetermined conditions, the inflatable element being initially stored in a non-linear recess, channel or housing provided in the motor vehicle extending above the door opening of the motor vehicle, the inflatable element having an upper edge provided with anchoring means connected to points within the recess, channel or housing, the inflatable element having a first chamber adjacent the upper edge thereof adapted to be inflated, and also having a second discrete chamber adjacent the lower edge thereof, said second chamber being of elongate form and being associated with anchoring means to anchor opposite ends of the second chamber to fixed points in the motor vehicle, the second chamber being configured so that the length of the lower edge of the inflatable element is reduced on inflation of the second chamber to tension the lower edge of the inflatable element, the fabric defining the first chamber being of greater porosity than the fabric forming the second chamber.
Conveniently the first chamber is adapted, on inflation, to remain inflated for a period of at least one second.
Advantageously the second chamber is adapted, on inflation, to remain inflated for a period of at least three seconds.
Preferably the portion of the inflatable element defining the first chamber is only loosely connected to the portion of the inflatable element defining the second chamber.
Conveniently the region of the inflatable element connecting the first chamber and the second chamber is formed from warp threads and weft threads that are not inter-woven.
In an alternative arrangement the region of the inflatable element inter-connecting the first chamber and the second chamber is fabricated solely from warp (or weft) threads, the weft (or warp) threads and any coating applied thereto having been cut-away.
Conveniently the gas generator means comprises a first gas generator associated with the first chamber and a second gas generator associated with the second chamber.
In an alternative embodiment the gas generator means comprises a single gas generator connected to the first chamber and the second chamber, the gas generator being connected to the second chamber by means of a non-return valve.
Conveniently the gas generator means are associated with sensor means adapted to sense the side impact, the gas generator means being actuated in response to a sensed side impact.
Advantageously the second chamber comprises a plurality of cells, each configured to have a substantially cylindrical form on inflation, the axis of each cell extending generally transversely of the axis of the chamber, the axis of each cell thus intersecting the lower edge of the inflatable element.
Conveniently the first chamber has a first region comprising a plurality of cells, and a second region comprising at least one cell, the regions being interconnected by a gas duct, the first region and the second region being separated by an uninflatable region of the inflatable element.
Advantageously the inflatable element is fabricated using a one-piece weaving technique.
Preferably the fabric forming the inflatable element is coated, there being less coating applied to the fabric defining the first chamber, than is applied to the fabric defining the second chamber.
In one embodiment the fabric forming the first chamber of the inflatable element is fabricated using fewer threads than the fabric forming the second chamber.